Cool, Dan, most of my focus is on extreme climates. San Bernardino county, where incense cedar is native, is probably much closer in climate to the op than the Warner mountains. Receives 16 inches of rain per year, and has a high temperature of 117 recorded. Incense cedar goes pretty dormant in the summer Dan, and requires less than one inch of rain per month during this time. Incense Cedar; Calocedrus decurrens "Another San Bernadino County Native. These trees should be planted with much more regularity in the High Desert. Flat dark green sprays of foliage and absolutely beautiful scaly, cinnamon colored bark. As the name implies, these trees are very aromatic and when grown as a large specimen, are impressive. You can find a few around Yucca Valley and Joshua Tree; my friends Sam and Michelle have a couple on their property off Buena Vista that are regal! This little guy is about 4 years old, planted as small seedling. It's about 2' high now. I think it's getting ready to start putting on substantial growth. It is not on irrigation, just what it gets from a hose on occasion (rare occasion..)" Here is a link that might be useful: HIgh Desert Pines

Just above freezing is perfect such as 40ºF which will keep the tree dormant over winter. So the greenhouse should be perfect. If it's put in a warm area, the tree will come out of dormancy too early and grow thin spindly growth that is very weak. Just keep the roots from freezing because if the roots freeze in the pots it is usually bad for any tree or plant and can kill it. You could also put the pot in a hole and bury the pot and then mulch around the tree and pot but this would be pretty risky since the plant is so young/tender right now. They are hardy down to zone 6b or 7a (-5 or 0ºF) They are deciduous and drop their leaves in late fall following the first hard frost.

Sorry about the damage to your son's tree. Not fun. I have to say, I am not a big fan of 'Desert Museum' palo verde trees. I know they are the "in" and trendy tree right now and are being planted everywhere, in commercial settings especially, but I think they are awfully lanky and gangly and subject to a lot of wind damage. They're popular because they grow very quickly, and low litter and generally thornless, but that quick growth makes their branches shoot up and look boring and weak (to me). I know, I know, a ton of people have them and love them, and I think the best ones are ones that get regular pruning and not too much water. I'm not saying I'd never try one if I ever moved to a new garden, but I would expect to have to prune it a lot to keep it looking nice and to keep it from getting storm damage and honestly, I just don't think a lot of plant sellers are telling people that part. Your son can prune his to try to create a shape he likes and that's a decent approach. I've seen some very nice ones around town, but again, they're getting regular pruning to thin them out and to make interesting branches. If he replaces it, I'd suggest getting a non-hybrid native Palo Verde if possible. In any case, he can defitely give it a good haircut and see how it progresses. Thinning out and removing a lot of the thin branches will help its appearance for sure. Good luck to him. Let's see what our other members say too. Take care, Grant

I was going to say the same thing. Your leaves also look a bit yellow which is another sign of too much water. Severe overwatering can look much like severe drought with the crispy leaves and all. I wouldn't water it at all until it's had a month of no rain or irrigation. Here's what Texas Native Plants Database has to say about it. ***Desert willow is a delicate, small, deciduous tree native to west Texas and the Edwards Plateau. Its long narrow leaves resemble those of willows (Salix spp.), although they are not related. Its flowers occur in showy clusters at the tips of the branches and on new wood, occurring from late spring to fall, depending on the rainfall. They are trumpet-shaped, sweetly fragrant, and range from light pink to light violet, rarely white or red. Its ability to withstand arid conditions, beautiful flowers and long flowering period make it one of Texas's best small native trees. It is easily cultivated but must have a well-drained site and must not be overwatered; in areas with more than 30 inches of annual rainfall, it must be planted in raised beds and watered carefully, especially in winter. Growth is irregular and requires attention to early trunk development. It can be pruned to a tree or shrub; since it blooms on new wood, the more it is pruned, the more it flowers. Plant Habit or Use: small tree Exposure: sun Flower Color: white to lavender-maroon, bicolors Blooming Period: summer fall Fruit Characteristics: long, narrow two-valved pod containing small flattened winged seeds Height: 15 ft. to 20 ft. (30 ft.) Width: 15 ft. to 20 ft. Plant Character: deciduous Heat Tolerance: very high Water Requirements: low Soil Requirements: adaptable USDA Hardiness Zone: 7*** Hope that helps. Kristi